Global Warming Hinders Species' Recovery After Mass Extinction

Researchers have discovered that global warming is the reason plants and animals had a hard time recovering from the largest mass extinction in Earth’s history 250 million years ago.

Nov 05, 2012

In this study, it was found that species that did survive extinction didn’t fully recover for 5 million years due to the environmental consequences of rising temperatures. The study adds a new chapter to the story of how life was forever altered by giant volcanic eruptions in the Early Triassic period – an event now called the “Great Dying” – and offers clues as to how climate change might impact life today, said Ohio State University doctoral student Alexa Sedlacek.

Sedlacek and Saltzman analyzed sedimentary rock formed on a tropical ocean floor 250 million years ago. Chemicals they found in the rock confirm that after the volcanic eruptions of the Great Dying, huge amounts of the Earth’s surface were being weathered away by greenhouse gases in the atmosphere. Earth’s climate was chemically altered as a result and the ocean was highly acidic, clogged with sediment, and warm as a modern hot tub.

“Extinctions are still happening today,” ‘’Sedlacek said. “And though things were much worse back then, the greenhouse gases that were made by volcanoes are analogous to the man-made greenhouse gases we have today. So our findings have the power to inform us about modern climate change.”

The researchers studied chemical elements in samples of limestone taken from northern Iran, which was a shallow tropical ocean during the Early Triassic period, from about 252 to 248 million years ago. The study provides the first-ever link between the elements strontium and carbon that were deposited in the rock at that time. Both changed in ways that indicate dramatic climate change was taking place in the world above.

Colleagues at the University of Cincinnati, who worked with the Austrian researchers, demonstrated that large amounts of sediment were collecting in the ocean. They then sent the samples to Ohio State, where Sedlacek and Saltzman measured the ratio of two forms of strontium, which is an indicator of how much bedrock was being weathered away from the Earth’s surface. This means that for species that did survive the Great Dying, the oceans were a very inhospitable place.

“It was a game-changer, biologically. Fish would have had silt in their gills, coral reefs would have been buried – as far as we can tell, the things that truly thrived in the ocean during that time were microbes,” Sedlacek said.

Taken together, these findings explain why life took so long to recover from the Great Dying – and may imply that life on Earth today will face similar problems in trying to recover from the current climate change.